In general, in order to fix a flush-type car speaker, an opening for receiving the speaker and threaded holes for fixing the speaker are formed at desired positions on a panel of a door or a rear tray of a car so that a projected back portion of the speaker may be received and fitted in the opening and the speaker may be fixed by screws. For cutting the opening and the holes, it is essential to prepare and use patterns of the opening and the holes because it is difficult to conform the opening and the holes on the panel to the contour of the projected back portion of the speaker and to the screw openings of the speaker, respectively, without using the patterns.
There has therefore been proposed a package case having, on one face thereof, a pattern for the speaker mounting so as to facilitate the installation of the speaker. However, such a known package case has instructions for mounting a speaker on another face of the package case than the face on which the pattern is formed. Therefore, in the actual speaker mounting operation, not only a fragment of the case on which the pattern is formed, but also, a fragment of the case on which the instructions are described must be brought into a limited space in the car. It is difficult to handle the bulky fragments in the narrow space and there is some difficulty even in reading the instructions.